In high bit rate fiber-optic communication systems, chromatic dispersion in transmission fibers is a critical distance-related factor. Chromatic dispersion is a property of an optical fiber that causes different wavelengths propagate along the fiber at different speeds. Chromatic dispersion causes the signal to become more distorted as the signal propagates along the fiber. Chromatic dispersion of a fiber varies as the fiber ages or because of environmental factors, such as changes of temperature, atmospheric pressure, and the like. Without special compensation techniques, chromatic dispersion imposes a limit on a transmission distance and a modulation bit rate of a fiber-optic communication system.
In a conventional fiber-optic communication system, data is transmitted through a transmission fiber at a fixed optical wavelength and the transmission fiber is associated with one or more dispersion compensation modules (DCMs) disposed at the transmitter and/or receiver terminals of the system. The wavelength dependency of the DCMs is selected to either cancel or reduce to an acceptable level the chromatic dispersion of the transmission fiber over the wavelength band of interest.
However, such means of compensating chromatic dispersion add to already high complexity and high cost of the fiber-optic communication systems.